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10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/slab.h>
15#include <linux/platform_device.h>
16#include <linux/watchdog.h>
17#include <linux/uaccess.h>
18#include <linux/gpio.h>
19#include <linux/of_gpio.h>
20#include <linux/delay.h>
21#include <linux/bitops.h>
22
23#define NUM_GPIOS 6
24
25enum a21_wdt_gpios {
26 GPIO_WD_ENAB,
27 GPIO_WD_FAST,
28 GPIO_WD_TRIG,
29 GPIO_WD_RST0,
30 GPIO_WD_RST1,
31 GPIO_WD_RST2,
32};
33
34struct a21_wdt_drv {
35 struct watchdog_device wdt;
36 struct mutex lock;
37 unsigned gpios[NUM_GPIOS];
38};
39
40static bool nowayout = WATCHDOG_NOWAYOUT;
41module_param(nowayout, bool, 0);
42MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
43 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
44
45static unsigned int a21_wdt_get_bootstatus(struct a21_wdt_drv *drv)
46{
47 int reset = 0;
48
49 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST0]) ? (1 << 0) : 0;
50 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST1]) ? (1 << 1) : 0;
51 reset |= gpio_get_value(drv->gpios[GPIO_WD_RST2]) ? (1 << 2) : 0;
52
53 return reset;
54}
55
56static int a21_wdt_start(struct watchdog_device *wdt)
57{
58 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
59
60 mutex_lock(&drv->lock);
61
62 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 1);
63
64 mutex_unlock(&drv->lock);
65
66 return 0;
67}
68
69static int a21_wdt_stop(struct watchdog_device *wdt)
70{
71 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
72
73 mutex_lock(&drv->lock);
74
75 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
76
77 mutex_unlock(&drv->lock);
78
79 return 0;
80}
81
82static int a21_wdt_ping(struct watchdog_device *wdt)
83{
84 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
85
86 mutex_lock(&drv->lock);
87
88 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 0);
89 ndelay(10);
90 gpio_set_value(drv->gpios[GPIO_WD_TRIG], 1);
91
92 mutex_unlock(&drv->lock);
93
94 return 0;
95}
96
97static int a21_wdt_set_timeout(struct watchdog_device *wdt,
98 unsigned int timeout)
99{
100 struct a21_wdt_drv *drv = watchdog_get_drvdata(wdt);
101
102 if (timeout != 1 && timeout != 30) {
103 dev_err(wdt->dev, "Only 1 and 30 allowed as timeout\n");
104 return -EINVAL;
105 }
106
107 if (timeout == 30 && wdt->timeout == 1) {
108 dev_err(wdt->dev,
109 "Transition from fast to slow mode not allowed\n");
110 return -EINVAL;
111 }
112
113 mutex_lock(&drv->lock);
114
115 if (timeout == 1)
116 gpio_set_value(drv->gpios[GPIO_WD_FAST], 1);
117 else
118 gpio_set_value(drv->gpios[GPIO_WD_FAST], 0);
119
120 wdt->timeout = timeout;
121
122 mutex_unlock(&drv->lock);
123
124 return 0;
125}
126
127static const struct watchdog_info a21_wdt_info = {
128 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
129 .identity = "MEN A21 Watchdog",
130};
131
132static const struct watchdog_ops a21_wdt_ops = {
133 .owner = THIS_MODULE,
134 .start = a21_wdt_start,
135 .stop = a21_wdt_stop,
136 .ping = a21_wdt_ping,
137 .set_timeout = a21_wdt_set_timeout,
138};
139
140static struct watchdog_device a21_wdt = {
141 .info = &a21_wdt_info,
142 .ops = &a21_wdt_ops,
143 .min_timeout = 1,
144 .max_timeout = 30,
145};
146
147static int a21_wdt_probe(struct platform_device *pdev)
148{
149 struct device_node *node;
150 struct a21_wdt_drv *drv;
151 unsigned int reset = 0;
152 int num_gpios;
153 int ret;
154 int i;
155
156 drv = devm_kzalloc(&pdev->dev, sizeof(struct a21_wdt_drv), GFP_KERNEL);
157 if (!drv)
158 return -ENOMEM;
159
160
161 node = pdev->dev.of_node;
162
163 num_gpios = of_gpio_count(node);
164 if (num_gpios != NUM_GPIOS) {
165 dev_err(&pdev->dev, "gpios DT property wrong, got %d want %d",
166 num_gpios, NUM_GPIOS);
167 return -ENODEV;
168 }
169
170 for (i = 0; i < num_gpios; i++) {
171 int val;
172
173 val = of_get_gpio(node, i);
174 if (val < 0)
175 return val;
176
177 drv->gpios[i] = val;
178 }
179
180
181 for (i = 0; i < num_gpios; i++) {
182 ret = devm_gpio_request(&pdev->dev, drv->gpios[i],
183 "MEN A21 Watchdog");
184 if (ret)
185 return ret;
186
187 if (i < GPIO_WD_RST0)
188 ret = gpio_direction_output(drv->gpios[i],
189 gpio_get_value(drv->gpios[i]));
190 else
191 ret = gpio_direction_input(drv->gpios[i]);
192 if (ret)
193 return ret;
194 }
195
196 mutex_init(&drv->lock);
197 watchdog_init_timeout(&a21_wdt, 30, &pdev->dev);
198 watchdog_set_nowayout(&a21_wdt, nowayout);
199 watchdog_set_drvdata(&a21_wdt, drv);
200
201 reset = a21_wdt_get_bootstatus(drv);
202 if (reset == 2)
203 a21_wdt.bootstatus |= WDIOF_EXTERN1;
204 else if (reset == 4)
205 a21_wdt.bootstatus |= WDIOF_CARDRESET;
206 else if (reset == 5)
207 a21_wdt.bootstatus |= WDIOF_POWERUNDER;
208 else if (reset == 7)
209 a21_wdt.bootstatus |= WDIOF_EXTERN2;
210
211 ret = watchdog_register_device(&a21_wdt);
212 if (ret) {
213 dev_err(&pdev->dev, "Cannot register watchdog device\n");
214 goto err_register_wd;
215 }
216
217 dev_set_drvdata(&pdev->dev, drv);
218
219 dev_info(&pdev->dev, "MEN A21 watchdog timer driver enabled\n");
220
221 return 0;
222
223err_register_wd:
224 mutex_destroy(&drv->lock);
225
226 return ret;
227}
228
229static int a21_wdt_remove(struct platform_device *pdev)
230{
231 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
232
233 dev_warn(&pdev->dev,
234 "Unregistering A21 watchdog driver, board may reboot\n");
235
236 watchdog_unregister_device(&drv->wdt);
237
238 mutex_destroy(&drv->lock);
239
240 return 0;
241}
242
243static void a21_wdt_shutdown(struct platform_device *pdev)
244{
245 struct a21_wdt_drv *drv = dev_get_drvdata(&pdev->dev);
246
247 gpio_set_value(drv->gpios[GPIO_WD_ENAB], 0);
248}
249
250static const struct of_device_id a21_wdt_ids[] = {
251 { .compatible = "men,a021-wdt" },
252 { },
253};
254
255static struct platform_driver a21_wdt_driver = {
256 .probe = a21_wdt_probe,
257 .remove = a21_wdt_remove,
258 .shutdown = a21_wdt_shutdown,
259 .driver = {
260 .name = "a21-watchdog",
261 .of_match_table = a21_wdt_ids,
262 },
263};
264
265module_platform_driver(a21_wdt_driver);
266
267MODULE_AUTHOR("MEN Mikro Elektronik");
268MODULE_DESCRIPTION("MEN A21 Watchdog");
269MODULE_LICENSE("GPL");
270MODULE_ALIAS("platform:a21-watchdog");
271
